Novel Endosymbionts in Rhizarian Amoebae Imply Universal Infection of Unrelated Free-Living Amoebae by Legionellales

Legionellales-infected water is a frequent cause of local outbreaks of Legionnaires’ disease and Pontiac fever. Decontaminations are difficult because Legionellales reproduce in eukaryotic microorganisms (protists). Most often, Legionellales have been isolated from amoebae; however, the culture-based sampling methods are taxonomically biased. Sequencing studies show that amoebae in the cercozoan class Thecofilosea are dominant in soils and wastewater treatment plants, prompting us to screen their capability to serve as potential hosts of endosymbiotic bacteria. Environmental isolates of Thecofilosea contained a surprising richness of endosymbiotic Legionellales, including Legionella. Considering the widespread dispersal of Legionellales in apparently unrelated amoeboid protist taxa, it appears that the morphotype and not the evolutionary origin of amoebae determines their suitability as hosts for Legionellales. We further provide a protocol for gnotobiotic cultivation of Legionellales and their respective hosts, facilitating future genomic and transcriptomic research of host–symbiont relationships.

Legionella spp. in Polish hospitals in 2009–2013 and 2014–2016: An epidemiological analysis

Introduction: Bacteria of the genus Legionella cause Legionnaires’ disease (atypical pneumonia, often with a severe clinical course) and Pontiac fever (self-limiting infection with flu-like symptoms). Legionella spp. are commonly found in natural aquatic environments and artificial water distribution systems. Material&Methods: An epidemiological analysis of Legionella spp. in hospital water supply systems was based on the results obtained from Sanitary-Epidemiological Stations of Poland. The materials for this study were hot water samples collected from 346 hospitals in 2009–2013 and from 221 hospitals in 2014–2016. Results: Between 2014 and 2016, there was a decrease in the percentage of the number of water samples in Group A (<100 CFU/100 ml). In other groups: B (>100 CFU/100 ml), C (>1000 CFU/100 ml), D (>10 000 CFU/100 ml) was observed an increase in the percentage of the number of water samples, which was a negative phenomenon. The mean number of L. pneumophila colonies in analyzed periods 2009–2013 and 2014–2016 were different. In 2009–2013, the most virulent L. pneumophila serogroup 1 (SG 1) was detected in 3 hospitals (0.9%), and L. pneumophila SG 2-14 were isolated in 20 (5.5%). Between 2014 and 2016, L. pneumophila SG 1 and L. pneumophila SG 2-14 were found in 5 hospitals (2.2%) and 18 hospitals (8.1%), respectively. Disscusion: In this study a comparative epidemiological analysis was performed on the prevalence of L. pneumophila in hospital water supply systems in Poland in the following two periods: 2009 –2013 and 2014–2016. The study demonstrated that the water supply systems of Polish hospitals were colonized by L. pneumophila at different levels. However, between 2014 and 2016 an upward trend was observed in comparison with 2009–2013.

Computational framework for evaluating risk trade-offs in costs associated with Legionnaires’ Disease risk, energy, and scalding risk for hospital hot water systems

Legionella pneumophila are bacteria that when inhaled cause Legionnaires’ Disease (LD) and febrile illness Pontiac Fever. As of 2014, LD is the most frequent cause of waterborne disease outbreaks due...

Antimicrobial activity of the volatile phase of essential oils and their constituents on Legionella pneumophila

Pathogenic bacteria of the genus Legionella cause atypical pneumonia known as Legionnaires’ disease and flu – like disease known as Pontiac fever. As pathogens of the respiratory system, these bacteria represent a public health problem and there is a need for examine new alternative ways to inactivate them. These bacteria live naturally in water and are transmitted by infectious aerosols. To purify the air, essential oils that show antimicrobial properties are widely used. The anti-Legionella activity of five exotic essential oils and five Mediterranean essential oils characteristic for coastal Croatia was examined. Model organism used in experiments was L. pneumophila (strain 130b). This experiment was conducting with modified version of sealed plate method using a BCYE medium. The exotic essential oil with highest anti-Legionella activity was Niaouli essential oil, and the best anti-Legionella activity among Mediterranean essential oils showed Immortelle essential oil. Anti- Legionella activity of four main chemical compounds was examined and compound that show significant highest anti-Legionella activity was α – pinene. Volatile components of essential oils have a great potential as anti-Legionella agents and further research are needed.

Legionella pneumophila and Protozoan Hosts: Implications for the Control of Hospital and Potable Water Systems

Legionella pneumophila is an opportunistic waterborne pathogen of public health concern. It is the causative agent of Legionnaires’ disease (LD) and Pontiac fever and is ubiquitous in manufactured water systems, where protozoan hosts and complex microbial communities provide protection from disinfection procedures. This review collates the literature describing interactions between L. pneumophila and protozoan hosts in hospital and municipal potable water distribution systems. The effectiveness of currently available water disinfection protocols to control L. pneumophila and its protozoan hosts is explored. The studies identified in this systematic literature review demonstrated the failure of common disinfection procedures to achieve long term elimination of L. pneumophila and protozoan hosts from potable water. It has been demonstrated that protozoan hosts facilitate the intracellular replication and packaging of viable L. pneumophila in infectious vesicles; whereas, cyst-forming protozoans provide protection from prolonged environmental stress. Disinfection procedures and protozoan hosts also facilitate biogenesis of viable but non-culturable (VBNC) L. pneumophila which have been shown to be highly resistant to many water disinfection protocols. In conclusion, a better understanding of L. pneumophila-protozoan interactions and the structure of complex microbial biofilms is required for the improved management of L. pneumophila and the prevention of LD.

1606. Legionellosis Cluster Associated with Direct and Indirect Hot Tub Exposure—West Virginia, 2018

Background In October 2018, the West Virginia Bureau for Public Health (BPH) notified CDC of one Legionella urinary antigen test (UAT)-positive case of Legionnaires’ disease (LD) in a worker at a racetrack facility. Following investigation by BPH and the county health department, five additional LD cases were identified among facility workers within a one-month period. Our objective was to determine the extent of the outbreak and identify potential sources of exposure. Methods We interviewed the previously identified patients and conducted case-finding among racetrack workers. Our case definitions included confirmed LD (pneumonia with a positive UAT), suspected LD (pneumonia without a UAT completed), and Pontiac fever (PF) (self-limited, nonspecific flu-like symptoms) among employees with exposure to the facility within 14 days prior to symptom onset. We conducted an environmental assessment of the facility and the surrounding area for sources of potential Legionella exposure. Results We identified 17 cases (71% in men, 35% in current smokers, median age 55 years): six confirmed LD, four suspected LD, and seven suspected PF cases. Our environmental assessment revealed a poorly maintained hot tub in the first floor jockey area. All samples collected from the hot tub (which was chlorinated before our arrival) tested negative for Legionella. Two employees with confirmed LD (33%), three with suspected LD (75%), and six with suspected PF (86%) had direct exposure to the hot tub or adjacent hallway; the remaining six were exposed only to a second floor office suite. Further investigation identified deficiencies in the facility’s ventilation systems and a crack in the floor between the hot tub and office areas. These factors created a pathway for Legionella-containing aerosols from the hot tub to pass into the second floor office space and air-handling unit for recirculation to occupied areas. Conclusion Our investigation suggests that both direct and indirect exposure to a Legionella reservoir can cause illness. This finding supports analysis of ventilation systems and airflow dynamics in future LD outbreak investigations. Clinicians should consider LD in pneumonia patients with direct or indirect exposure to suspected Legionella sources to ensure appropriate testing and treatment. Disclosures All authors: No reported disclosures.

Legionellosis in Poland in 2017

ABSTRACT OBJECTIVE. The aim of this study is to assess the epidemiological situation of legionellosis in Poland in 2017 in comparison with previous years. MATERIAL AND METHODS. The analysis is based on national surveillance data published in the annual bulletin: “Infectious diseases and poisonings in Poland in 2017” and bulletins from previous years along with data from legionellosis case reports collected and sent to the Department of Epidemiology of Infectious Diseases and Surveillance NIPH – NIH by Sanitary and Epidemiological Stations. RESULTS. In Poland, both cases of Legionnaires’ disease (an acute form of infection with pneumonia) and Pontiac fever (a mild, influenza-like form of infection) are routinely reported to the surveillance system. In 2017, a total of 39 cases of legionellosis were registered, including 38 cases of Legionnaires’ disease and 1 case of Pontiac fever; the annual incidence rate 0.102 (per 100,000 population) has increased by almost 50 percent since previous year (0.070) and is almost three times higher than the median incidence (0.036) for 2011-2015. The infections were reported in fourteen voivodeships; only one voivodeship (Świętokrzyskie) did not register any case in last years. The incidence in men (0.129 per 100,000) was higher compared to women (0.076); the highest incidence (0.323) was noted in men aged 50-59. All reported cases were sporadic and were hospitalised. The Sanitary Inspection reported nine fatal cases – 6 women and 3 men. Thirty three cases were autochthonous including four cases linked with contaminated water systems in health-care settings. Six cases were associated with travels abroad (to Egypt, Albania, Italy and Crete). SUMMARY AND CONCLUSIONS. Although in recent years number of reported cases continues to rise, the incidence of legionellosis in Poland remains one of the lowest in the entire EU. Also draws attention variation of incidence between provinces and a high mortality among reported cases. Our data suggest significant under-diagnosis of legionellosis. A priority remains to improve early diagnosis of Legionnaires’ disease in health care settings.